A number of industries, such as the mining industry, rely on large mobile machines (e.g., off-road haul trucks and wheel loaders) to transport cargo loads. The loads can be very large, and the machines are often operated around the clock. As the mobile machine travels, tires of the mobile machine generate heat due to friction with the road surface.
One way to quantify the heat generation of a tire is by calculating the tire's ton-miles-per-hour (TMPH). A tire's TMPH (or ton-kilometers-per-hour, TKPH) may be proportional to the product of, for example, a payload of the mobile machine and a speed of the mobile machine. High TMPH values can indicate excessive amounts of heat generation, and excessive heat generation can lead to accelerated wear and failure of the mobile machine's tires. Due to the large cost of replacing tires, it is desirable to keep the tire's TMPH generally below a predetermined value.
One approach to limiting heat generation in mobile machine tires is disclosed in U.S. Pat. No. 6,842,680 (the '680 patent) issued to Doddek et al. on Jan. 11, 2005. The '680 patent discloses an apparatus for controlling the speed of a machine based on the ton-miles-per-hour of the machine. The apparatus includes a payload monitor adapted to generate a signal related to the weight of the machine and a speed monitor adapted to generate a signal related to the speed of the machine. Additionally the '680 patent discloses a vehicle information system having a processor and a database for transmitting and receiving a plurality of signals. The vehicle information system monitors the machine speed and compares an actual ton-miles-per-hour value to a percentage of a predetermined ton-miles-per-hour value (i.e., a ton-miles-per-hour limit). If the actual ton-miles-per-hour value exceeds the ton-miles-per-hour limit, the apparatus reduces the machine speed.
Although the apparatus of the '680 patent may use TMPH calculations to reduce machine speed and thus improve tire wear, it may still be improved. For example, in cases where the mobile machine is utilized in an operation involving multiple machines, limiting the speed of one machine can diminish the productivity of other machines by creating a bottleneck (e.g., when a second machine depends on the limiting machine, and a third machine depends on the second machine, etc.).
The disclosed machine system is directed to overcoming one or more of the problems set forth above.